The First Lady of the United States is inside the guest house of Hamburg before anti-G20 protests

Hamburg: First lady of the United States, Melania Trump, stayed at her guest house in Hamburg on Friday because of protests against the G20, her spokeswoman said.

An event program in the northern German city involving Trump and other spouses of political leaders has had to be severely curtailed due to the demonstrations.

“The Hamburg police could not give us permission to leave (the residence),” said Trump spokeswoman Stephanie Grisham.

Instead of a visit to a climate center, the spouses will be treated with presentations from climate scientists at a Hamburg hotel.

German news agency DPA reported that the 47-year-old Trump could not join the others on a tour of the port of Hamburg on Friday.

Overnight protests saw police shoot water cannons and tear gas in battles with a hard core of far-left activists, leaving 159 officers and an unspecified number of injured protesters.

Protests resumed early Friday with activists burning cars, smashing windows and even firing flares at police helicopters and grazing tires on Canadian delegation cars.

Small groups played cat and mouse with the police blocking the traffic and trying to stop the leaders from reaching the summit headquarters.

There are currently 20,000 police officers in service for the two-day summit that began Friday, backed by helicopters, water cannon trucks and surveillance drones.

But police, already backed by officials from elsewhere in Germany and Austria, have called for reinforcements, a Hamburg police spokesman said.